(a) Field of the Invention
The present invention generally relates to an apparatus and method for producing a closure member of a closure profile. More particularly, the invention relates to an apparatus and method for producing a first multi-colored closure member adapted to interlock with a second multi-colored closure member, where color interaction among specific portions of the closure members reveals imperfections in closure.
(b) Description of the Prior Art
In recent years, there has been an increase in the use of recloseable bags for preserving or storing such items as food. Some of these stored items require a tightly sealed bag to prevent leakage of the bag's contents. The seal of the bag will hereinafter be referred to as the closure profile of the bag. The closure profile typically includes two closure members which interlock with each other to seal the bag. In order for the bag to be tightly sealed, its closure members must be completely interlocked over the entire length of the bag's mouth. Where the closure members are of the same color (e.g., clear or white), a person can only insure that there is a tight seal by making a physical check of the interlocked closure members. Often, a person can be confident that a tight seal has been obtained only by running his/her hand across the closure profile many times.
one bag used in recent years has two closure members of different colors. The bag uses a color change to indicate that the closure members are properly interlocked. For example, some recloseable bags presently marketed have a yellow closure member and a blue closure member which result in a green color along the closure profile when the bag is sealed. Although the colored closure members make it easy to line up the two closure members before interlocking them, the color change upon interlocking the closure members does not readily reveal an imperfect closure. For instance, if the closure members are yellow and blue and the closure is imperfect, the entire length of the closure profile will still appear green except upon extremely close visual examination. Only a physical check ensures that the two closure members are completely interlocked.
One type of colored interlocking closure device is described and illustrated in U.S. Pat. No. 4,285,105 to Kirkpatrick. The Kirkpatrick patent discloses the use of different colors for the two closure members so that one can observe the completeness of the occlusion of the closure. An illustrative embodiment disclosed by the Kirkpatrick patent is that the closure members can be primary colors and sufficiently translucent (e.g., red and yellow) so that occlusion of the closure numbers produces a visible secondary color (e.g., orange).
While the use of different colors for the two closure members has been used extensively in recent years, it does not allow for simple visual verification of complete occlusion of the closure members. People must still run their hands across the length of the closure profile more than once to insure that there is a tight seal. Consequently, a need exists for improvement in the design of the closure profile so that complete occlusion of the closure members can be easily visually verified.
The closure profile of recloseable bags presently on the market have monochromatic closure members, where one closure member is all one color and the other closure member is all the same or another color. The apparatus for producing a closure profile of a recloseable bag is relatively simple in design. The apparatus typically consists of an adaptor plate and a die plate connected to the adaptor plate. To produce a closure profile with two closure elements of the same color, a single melted material is first fed into an input port in the die plate. The melted material then flows through one or two channels in the die plate and leaves the die plate approximately in the form of each of the closure members. If each of the closure members is being extruded through separate output ports in the die plate, the die plate will contain two channels, one for extruding one closure member and the other for extruding the other closure member. If the two closure members are being extruded through a single output port through the die plate and cut apart later on, the die plate contains a single channel which extrudes both closure members together.
To produce a closure profile with the two closure members being of different colors, two melted materials having different colors are fed through two input ports in the die plate. The die plate has two separate channels cut through it, one for each color, with each channel producing one of the closure members.
Since a closure profile with monochromatic closure members does not allow for easy visual verification of proper closure, a need exists for a new and useful closure profile with improved color interaction among its two closure members. In addition, a need exists for an apparatus which can produce such a new and useful closure profile.